// 接口的继承
interface A{
    id:number;
}
interface B extends A{
    name:string;
}

// 接口的合并
interface A{
    age:number
}

let db:B={
    id:1,
    name:"db",
    age:66
}

//字面量类型
let ZML:"hello";
/*只能是hello*/
ZML="hello";

let ZML2:"left" | "right";
ZML2="left"
ZML2="right"

export {db}